abi

Documentation

Overview

Package abi implements the VNT ABI (Application Binary Interface).

The VNT ABI is strongly typed, known at compile time and static. This ABI will handle basic type casting; unsigned to signed and visa versa. It does not handle slice casting such as unsigned slice to signed slice. Bit size type casting is also handled. ints with a bit size of 32 will be properly cast to int256, etc.

Index

• Constants
• func KeyType(tp string) int32
• func U256(n *big.Int) []byte
• type ABI
  • func JSON(reader io.Reader) (ABI, error)
  • func (abi *ABI) MethodById(sigdata []byte) (*Method, error)
  • func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error)
  • func (abi *ABI) UnmarshalJSON(data []byte) error
  • func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error)
  • func (abi ABI) UnpackInput(v interface{}, name string, input []byte) (err error)
• type Argument
  • func (argument *Argument) UnmarshalJSON(data []byte) error
• type Arguments
  • func (arguments Arguments) LengthNonIndexed() int
  • func (arguments Arguments) NonIndexed() Arguments
  • func (arguments Arguments) Pack(args ...interface{}) ([]byte, error)
  • func (arguments Arguments) PackValues(args []interface{}) ([]byte, error)
  • func (arguments Arguments) Unpack(v interface{}, data []byte) error
  • func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error)
• type Connector
• type Event
  • func (e Event) Id() common.Hash
  • func (e Event) String() string
• type Extarg
• type Key
  • func (key *Key) KeyTraversal()
• type Method
  • func (method Method) Id() []byte
  • func (method Method) Sig() string
  • func (method Method) String() string
• type Node
  • func NewNode(fieldname string, fieldtype string, fieldlocation string) *Node
  • func (nd *Node) Add(fieldname string, fieldtype string, fieldlocation string, base string) *Node
  • func (nd *Node) Get(name string) (*Node, error)
  • func (nd *Node) Traversal(r Root)
• type Root
  • func (r Root) Fulling() Root
• type StorageType
• type Table
  • func (tbl Table) Traversal(sym string, key *Key)
  • func (table *Table) UnmarshalJSON(data []byte) error
• type Tables
• type Type
  • func NewType(t string) (typ Type, err error)
  • func (t Type) String() (out string)

Examples

• JSON

Constants

const (
	TY_INT32 int32 = 1 + iota
	TY_INT64
	TY_UINT32
	TY_UINT64
	TY_UINT256
	TY_STRING
	TY_ADDRESS
	TY_BOOL
	TY_POINTER
)

const (
	IntTy byte = iota
	UintTy
	BoolTy
	StringTy
	SliceTy
	ArrayTy
	MappingTy
	AddressTy
	FixedBytesTy
	BytesTy
	HashTy
	FixedPointTy
	FunctionTy
	StructTy
)

Type enumerator

Functions

func KeyType

func KeyType(tp string) int32

func U256

func U256(n *big.Int) []byte

U256 converts a big Int into a 256bit EVM number.

Types

type ABI

type ABI struct {
	Constructor Method
	Methods     map[string]Method
	Events      map[string]Event
	Calls       map[string]Method
}

The ABI holds information about a contract's context and available invokable methods. It will allow you to type check function calls and packs data accordingly.

func JSON

func JSON(reader io.Reader) (ABI, error)

JSON returns a parsed ABI interface and error if it failed.

Example

const definition = `[{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"isBar","outputs":[{"name":"","type":"bool"}],"type":"function"}]`

abi, err := JSON(strings.NewReader(definition))
if err != nil {
	log.Fatalln(err)
}
_, err = abi.Pack("isBar", common.HexToAddress("01"))

if err != nil {
	log.Fatalln(err)
}

//fmt.Printf("out: %x\n", out)

func (*ABI) MethodById

func (abi *ABI) MethodById(sigdata []byte) (*Method, error)

MethodById looks up a method by the 4-byte id returns nil if none found

func (ABI) Pack

func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error)

Pack the given method name to conform the ABI. Method call's data will consist of method_id, args0, arg1, ... argN. Method id consists of 4 bytes and arguments are all 32 bytes. Method ids are created from the first 4 bytes of the hash of the methods string signature. (signature = baz(uint32,string32))

func (*ABI) UnmarshalJSON

func (abi *ABI) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface

func (ABI) Unpack

func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error)

Unpack output in v according to the abi specification

func (ABI) UnpackInput

func (abi ABI) UnpackInput(v interface{}, name string, input []byte) (err error)

Unpack Input in v according to the abi specification

type Argument

type Argument struct {
	Name    string
	Type    Type
	Indexed bool // indexed is only used by events

}

Argument holds the name of the argument and the corresponding type. Types are used when packing and testing arguments.

func (*Argument) UnmarshalJSON

func (argument *Argument) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface

type Arguments

type Arguments []Argument

func (Arguments) LengthNonIndexed

func (arguments Arguments) LengthNonIndexed() int

LengthNonIndexed returns the number of arguments when not counting 'indexed' ones. Only events can ever have 'indexed' arguments, it should always be false on arguments for method input/output

func (Arguments) NonIndexed

func (arguments Arguments) NonIndexed() Arguments

NonIndexed returns the arguments with indexed arguments filtered out

func (Arguments) Pack

func (arguments Arguments) Pack(args ...interface{}) ([]byte, error)

Pack performs the operation Go format -> Hexdata

func (Arguments) PackValues

func (arguments Arguments) PackValues(args []interface{}) ([]byte, error)

PackValues performs the operation Go format -> Hexdata It is the semantic opposite of UnpackValues

func (Arguments) Unpack

func (arguments Arguments) Unpack(v interface{}, data []byte) error

Unpack performs the operation hexdata -> Go format

func (Arguments) UnpackValues

func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error)

UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification, without supplying a struct to unpack into. Instead, this method returns a list containing the values. An atomic argument will be a list with one element.

type Connector

type Connector struct {
	Name string
	Type string
}

type Event

type Event struct {
	Name      string
	Anonymous bool
	Inputs    Arguments
}

Event is an event potentially triggered by the EVM's LOG mechanism. The Event holds type information (inputs) about the yielded output. Anonymous events don't get the signature canonical representation as the first LOG topic.

func (Event) Id

func (e Event) Id() common.Hash

Id returns the canonical representation of the event's signature used by the abi definition to identify event names and types.

func (Event) String

func (e Event) String() string

type Extarg

type Extarg struct {
	Name        string
	Type        string
	StorageType uint64
	Tables      []Extarg
}

type Key

type Key struct {
	Name      string           `json:"name"`
	Tables    Tables           `json:"tables"`
	Types     map[string]Type  `json:"-"`
	Keys      map[string]Table `json:"keys"`
	Connector map[string][]string
}

func (*Key) KeyTraversal

func (key *Key) KeyTraversal()

type Method

type Method struct {
	Name    string
	Const   bool
	Inputs  Arguments
	Outputs Arguments
}

Method represents a callable given a `Name` and whether the method is a constant. If the method is `Const` no transaction needs to be created for this particular Method call. It can easily be simulated using a local VM. For example a `Balance()` method only needs to retrieve something from the storage and therefor requires no Tx to be send to the network. A method such as `Transact` does require a Tx and thus will be flagged `true`. Input specifies the required input parameters for this gives method.

func (Method) Id

func (method Method) Id() []byte

func (Method) Sig

func (method Method) Sig() string

Sig returns the methods string signature according to the ABI spec.

Example

function foo(uint32 a, int b)    =    "foo(uint32,int256)"

Please note that "int" is substitute for its canonical representation "int256"

func (Method) String

func (method Method) String() string

type Node

type Node struct {
	FieldName     string           `json:"name"`
	FieldType     string           `json:"type"`
	FieldLocation string           `json:"-"`
	StorageType   StorageType      `json:"storagetype"`
	Children      map[string]*Node `json:"children"`
	Tables        []*Node          `json:"tables"`
}

func NewNode

func NewNode(fieldname string, fieldtype string, fieldlocation string) *Node

func (*Node) Add

func (nd *Node) Add(fieldname string, fieldtype string, fieldlocation string, base string) *Node

func (*Node) Get

func (nd *Node) Get(name string) (*Node, error)

func (*Node) Traversal

func (nd *Node) Traversal(r Root)

type Root

type Root struct {
	Root map[string]*Node
}

func (Root) Fulling

func (r Root) Fulling() Root

type StorageType

type StorageType uint64

const (
	NormalTy StorageType = iota
	MappingKeyTy
	ArrayIndexTy
	MappingValueTy
	ArrayValueTy
	StructValueTy
	LengthTy
)

type Table

type Table struct {
	Name        string
	Type        Type
	StorageType uint64
	Tables      Tables
}

func (Table) Traversal

func (tbl Table) Traversal(sym string, key *Key)

func (*Table) UnmarshalJSON

func (table *Table) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler interface

type Tables

type Tables []Table

type Type

type Type struct {
	// Used by mapping type
	Key *Type

	Elem *Type

	Kind reflect.Kind
	Type reflect.Type
	Size int
	T    byte // Our own type checking
	// contains filtered or unexported fields
}

Type is the reflection of the supported argument type

func NewType

func NewType(t string) (typ Type, err error)

NewType creates a new reflection type of abi type given in t.

func (Type) String

func (t Type) String() (out string)

String implements Stringer